There are various methods for bonding two structural elements together including, but not limited to brazing, welding, adhesives, etc. Typically brazing involves applying a brazing material to the surfaces of one or both of the elements that are to be joined together. The elements then undergo a high temperature brazing process that melts the brazing material. If the elements are contacting one another, as the brazing material cools, the elements become substantially permanently coupled to one another. Welding typically involves melting the surfaces of one or both elements that are to be joined as well as a filler material. This creates a pool of molten material. As the molten material cools, a strong joint is formed. Adhesives typically are applied to one or both of the structural elements and as the adhesive cures, it forms a bond between the two elements, either chemical, electrostatic, or in some instances using Van der Waals forces.
All of these methods of bonding have inherent problems of subjecting the structural elements to various stresses both during the process and while the material cools to form the bond. In applications where the elements are not subject to movement or vibrations, these stresses typically go unnoticed. However, the additional stresses caused can create unwanted side effects if the elements are under consistent movement or vibration.
The flow meter industry, and in particular, the Coriolis flow meter industry faces a unique challenge in bonding elements together. For example, most flow meters include one or more flow conduits that are connected inline in a pipeline or other transport system to convey material, e.g., fluids, slurries and the like, in the system. Each conduit may be viewed as having a set of natural vibration modes including for example, simple bending, torsional, radial, and coupled modes. In a typical Coriolis mass flow measurement application, a conduit is excited in one or more vibration modes as a material flows through the conduit, and the motion of the conduit is measured at points spaced along the conduit. Excitation is typically provided by an actuator, e.g., an electromechanical device, such as a voice coil-type driver, that perturbs the conduit in a periodic fashion. Mass flow rate may be determined by measuring the time delay or phase differences between motion at the transducer locations. Typically, the flow meter will also include one or more brace bars, which can define a bending axis of the flow conduit. Typically, these brace bars are bonded to the flow conduit using a brazing, welding, or adhesion process. In most cases, the bonding process creates additional stresses in the flow conduit. Because the flow conduits are excited in one or more vibration modes, even relatively small stresses can significantly affect the meter's performance. Additionally, these bonding processes can be expensive and time consuming.
Therefore, there is a need to provide a method for reducing the stresses caused by bonding (brazing, welding, adhesives, etc.). Additionally, there is a need to provide a method for reducing the cost and time consumed in bonding elements together, and in particular, for bonding a brace bar to a flow conduit. The present invention overcomes these and other problems and an advance in the art is achieved.